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Попов, Виктор Владимирович

Организационные подразделения

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Попов

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Виктор Владимирович

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Материалы и процессы получения теплозащитных покрытий
(НИЯУ МИФИ, 2016) Попов, В. В.; Писарев, А. А.; Попов, Виктор Владимирович; Писарев, Александр Александрович
Рассмотрены основные вопросы, связанные с созданием современных теплозащитных покрытий. Выполнен анализ используемых и перспективных керамических оксидных материалов для теплозащитных покрытий, методов их синтеза, способов нанесения теплозащитных покрытий, а также возможных механизмов их разрушения. Монография предназначена для широкого круга специалистов, аспирантов и студентов, занимающихся изучением материалов теплозащитных покрытий и созданием самих теплозащитных покрытий.
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Crystalline structure formation and phase transitions in complex oxides Ln2Me2O7 (Ln = La - Lu; Me = Ti, Zr, Hf)
(2019) Tsarenko, N. A.; Popov, V. V.; Yastrebtsev, A. A.; Menushenkov, A. P.; Попов, Виктор Владимирович; Ястребцев, Алексей Алексеевич; Менушенков, Алексей Павлович
© 2019 Komarov Botanical Institute of the Russian Academy of Sciences. All rights reserved.Using X-ray diffraction and Raman spectroscopy, the authors of this paper investigated the formation and evolution of crystalline structure in complex oxides Ln2Me2O7 (Ln = La - Lu; Me = Ti, Zr, Hf), which occur as a result of calcination of amorphous precursors synthesized through coprecipitation from metal salt solutions. It is shown that the crystallization parameters and further phase transformations are largely governed by the cation radius ratio = rLn3+/rMe4+. In the case of zirconates and hafnates of rare earth elements (REE), nanocrystalline powders with fcc fluorite are initially formed during amorphous precursor crystallization. Further increase of the annealing temperature to _1,000 oC in the case of Ln = La - Dy leads to the phase transition fluorite → pyrochlore, the temperature of which rises and the intensity decreases as the REE radius gets smaller. The powders containing REEs with smaller cation radii retain their fluorite structure within the entire tempe rature range studied. For Yb2Zr2O7, it was found that _-phase was formed. In the case of rare earth titanates (Ln = Sm - Yb), crystallization of amorphous precursors directly resulted in a pyrochlore structure. For titanates of REEs with big cation radii (Ln = La - Nd), generation of layered perovskites was observed. Crystallite growth activation energies were calculated for the above mentioned types of phase transitions, which helped explain the sequence of structural transformations (amorphous phase → fluorite → pyrochlore) observed in rare earth zirconates and hafnates from the energy point of view. A good correlation was found between the X-ray diffraction and Raman spectroscopy data. It was concluded that Raman spectroscopy provides a more sensitive technique (versus X-ray diffraction) for studying the phase transitions occurring in complex rare earth oxides.
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Local Disorder in Ln2Ti2O7 (Ln = Gd, Tb, Dy) Pyrochlores
(2019) d'Acapito, F.; Puri, A.; Menushenkov, A. P.; Popov, V. V.; Gaynanov, B. R.; Ivanov, A. A.; Kuznetsov, A. V.; Yaroslavtsev, A. A.; Менушенков, Алексей Павлович; Попов, Виктор Владимирович; Гайнанов, Булат Радикович; Иванов, Андрей Анатольевич; Кузнецов, Алексей Владимирович
© 2019, Pleiades Publishing, Inc.The temperature dependences of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectra of Ln2Ti2O7 (Ln = Gd, Tb, Dy) geometrically frustrated magnets with a pyrochlore structure are presented. The temperature dependences of the Ln-O and Ti-O interatomic bond lengths and Debye-Waller factors σ2 characterizing the local static and dynamic disordering of bonds have been obtained in the temperature range of 10–300 K. The stiffnesses of metal-oxygen bonds and the parameters of local disordering of the structure have been determined from the dependences σ2(T). The effect of the magnetic state of rare-earth ions on local features of the Ln2Ti2O7 structure has been described. The characteristics of local disorder in pyrochlores under study have been compared to dysprosium zirconate Dy2Zr2O7 having a disordered fluorite structure.
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The effect of the synthesis conditions on the structure and phase transitions in Ln2(MoO4)3
(2021) Svetogorov, R. D.; Tsarenko, N. A.; Ponkratov, K. V.; Ognevskaya, N. V.; Popov, V. V.; Menushenkov, A. P.; Yastrebtsev, A. A.; Molokova, A. Y.; Rudakov, S. G.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Рудаков, Сергей Геннадьевич
© 2020 Elsevier Masson SASThe effect of the lanthanide cation type and calcination temperature on the structure and phase transitions in Ln2(MoO4)3 molybdates was studied using synchrotron X-ray diffraction, infrared and Raman spectroscopy, photoluminescence, simultaneous thermal analysis and inductively coupled plasma atomic emission spectroscopy. It was found that the crystallization of the precursors at 500∘ C/3 h results in the formation of nanocrystalline powders with the monoclinic structure (sp. gr. I112/b (15)) for Ln2(MoO4)3 (Ln = La–Ho), and a mixture of orthorhombic (sp. gr. Pnca(60)) and tetragonal (sp. gr. I41/a(88)) phases for Yb2(MoO4)3. A further increase in temperature to 1000∘ C leads to a significant rearrangement of the crystal structure, which is largely determined by the lanthanide type. The diagram of phase relations in the Ln2(MoO4)3 molybdates as a function of the Ln3+ cation radius and the calcination temperature has been refined. According to the results of Raman and IR spectroscopy, MoO4 tetrahedra are the main structural units in Ln molybdates. The increased hygroscopicity of heavy lanthanide molybdates (Ln = Ho, Yb) is associated with the presence of empty cavities in the orthorhombic structure. The photoluminescence spectra have shown that EuOn polyhedra in Eu2(MoO4)3 are distorted, and Eu3+ ions occupy several nonequivalent crystallographically different sites with a low symmetry point group.
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Influence of the lanthanide on the composition and structure of hydrated Ln chromates
(2021) Svetogorov, R. D.; Ognevskaya, N. V.; Tsarenko, N. А.; Seregina, O. N.; Popov, V. V.; Menushenkov, A. P.; Yastrebtsev, A. A.; Dubyago, F. E.; Rudakov, S. G.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Рудаков, Сергей Геннадьевич
© 2021 Institute of Physics Publishing. All rights reserved.The effect of the Ln3+ cation type on the composition and structure of a wide range of hydrated lanthanide chromates (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Yb, Y) has been studied. It was found that hydrated Ln chromates can be divided into several groups in terms of their composition and structure. The synthesized chromates of light lanthanides crystallize into heptahydrates [Ln2(CrO4)3(H2O)5]·2H2O (Ln = La, Pr, Nd, Sm) and tetrahydrate Eu2(CrO4)3·4H2O with a monoclinic structure (sp. gr. Р21/с). The chromates of heavy lanthanides (Ln = Gd, Dy, Ho, Yb, Y) remain X-ray amorphous.
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The synthesis and studies of crystal/local structures and morphology of hydrated molybdenum oxides
(2021) Khramov, E. V.; Zubavichus, Y. V.; Shchetinin, I. V.; Ponkratov, K. V.; Popov, V. V.; Menushenkov, A. P.; Yastrebtsev, A. A.; Molokova, A. Y.; Pisarev, A. A.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Писарев, Александр Александрович
© 2021 Elsevier Inc.The crystal/local structure and morphology of hydrated molybdenum oxides particles obtained by acidic precipitation of molybdates solutions were studied using X-ray diffraction, X-ray absorption spectroscopy, scanning electron microscopy, Raman and IR spectroscopy. The precipitation of ammonium heptamolybdate solutions (pH = 1.00) at room temperature result in the formation of poorly crystallized hydrated molybdenum oxides. At the same time, acidification of the sodium molybdate solutions does not lead to the appearance of precipitates for several days. Heating to 90 °C and aging the reaction suspension prepared from both ammonium heptamolybdate and sodium molybdate results in the formation of prismatic h-MoO3 particles with the hexagonal crystal structure. It was shown that distorted octahedra MoO6 are the basic structural units in the formed hydrated molybdenum oxides. Along with the presence of Mo[dbnd]O and Mo–O bonds, the presence of water molecules, hydroxyl ions, and NH4+ (or Na+) ions was detected in the structure of hydrated MoO3. The type of Mo salt and acid significantly affects the morphology of h-MoO3 particles. Large h-MoO3 particles are formed by aggregation of small ones and Ostwald ripening due to the “dissolution - precipitation” process.
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Reversible Valence Transition Eu-3+ ? Eu-2+ ? Eu-3+ in EuxEux Ox (2)+ (3)+ (M = Ti, Zr, Hf) 1-MO3+x /2 : An Analysis of XAFS and XRD Data
(2022) Menushenkov, A. P.; Popov, V. V.; Kuznetsov, A. V.; Molokova, A. Y.; Yastrebtsev, A. A.; Gaynanov, B. R.; Rudakov, S. G.; Менушенков, Алексей Павлович; Попов, Виктор Владимирович; Кузнецов, Алексей Владимирович; Ястребцев, Алексей Алексеевич; Гайнанов, Булат Радикович; Рудаков, Сергей Геннадьевич
The regularities of completely reversible valence transition Eu3+. Eu2+. Eu3+ in complex europium oxides have been investigated using a combination of X-ray diffraction (XRD) and X-ray absorption spectroscopy (XANES + EXAFS) synchrotron methods. The influence of the type of M4+ cations on the reduction and oxidation, as well as the formation and evolution of the crystalline and local structure of the (M = Ti, Zr, Hf) compounds is established. It is shown that oxidation of initially reduced Eu2+MO3 samples leads to the formation of mixed-valence (MV) state Eu2+/Eu3+ with inhomogeneous charge distribution, causing a phase transition with formation of partially amophized intermediate metastable phases Eu3+MO3.5 having a monoclinic structure (sp. gr..1211). An increase in the oxidative annealing temperature to 1000 degrees. facilitates further phase transition with the formation of stable cubic phases Eu M2O7.
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Features of the Phase Preferences, Long-and Short-Range Order in Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) with Their Relation to Hydration Behavior
(2022) Zubavichus, Y. V.; Svetogorov, R. D.; Khramov, E. V.; Tsarenko, N. A.; Popov, V. V.; Menushenkov, A. P.; Yastrebtsev, A. A.; Gaynanov, B. R.; Rudakov, S. G.; Ivanov, A. A.; Dubyago, F. E.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Гайнанов, Булат Радикович; Рудаков, Сергей Геннадьевич; Иванов, Андрей Анатольевич
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.The effect of synthesis conditions on the features of the long-and short-range order of Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) powders synthesized via coprecipitation of salts has been studied by a complex of physico-chemical techniques including synchrotron X-ray powder diffraction, X-ray absorption spectroscopy, Raman and infrared spectroscopy, and simultaneous thermal analysis. It was found that crystallization of amorphous precursors begins at 600 °C/3 h and leads to the formation of the monoclinic structure with sp. gr. C12/c1(15) for Ln2(WO4)3 (Ln = Gd, Dy) and with sp. gr. P121/a1(14) for Ln = Yb, whereas crystallization of Ho precursor requires even higher temperature. After annealing at 1000 °C, the P121/a1(14) phase becomes the dominant phase component for all heavy lanthanoid types except for Ln = Gd. It was shown that the Ln (Ln = Dy, Ho, and Yb) tungstates with the P121/a1(14) monoclinic structure correspond to trihydrates Ln2(WO4)3·3H2 O formed due to a rapid spontaneous hydration under ambient conditions. It was concluded that the proneness to hydration is due to a specific structure of the P121/a1(14) phase with large voids available to water molecules. Modifications in the local structure of Ln-O coordination shell accompanying the structure type change and hydration are monitored using EXAFS spectroscopy.
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Multiscale study on the formation and evolution of the crystal and local structures in lanthanide tungstates Ln2(WO4)3
(2022) Svetogorov, R. D.; Khramov, E. V.; Zubavichus, Y. V.; Tsarenko, N. A.; Popov, V. V.; Menushenkov, A. P.; Yastrebtsev, A. A.; Rudakov, S. G.; Ivanov, A. A.; Gaynanov, B. R.; Molokova, A. Y.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Рудаков, Сергей Геннадьевич; Иванов, Андрей Анатольевич; Гайнанов, Булат Радикович
© 2022 Elsevier B.V.The influence exerted by the specific type of the lanthanide cation and calcination temperature on the crystal and local structures of Ln2(WO4)3 tungstates (Ln = La–Dy) prepared by a coprecipitation is studied using synchrotron X-ray diffraction, X-ray absorption fine structure (XAFS) spectroscopy, Fourier transform infrared (FT-IR) and Raman spectroscopies, photoluminescence, simultaneous thermal analysis, and inductively coupled plasma atomic emission spectroscopy. The combination of these experimental techniques enabled a structural insight into Ln tungstates at multiple characteristic scales, i.e. short-range of metal atom coordination (XAFS), medium-range of the network of chemical bonds (FT-IR and Raman spectroscopies), and long-range or 3D periodicity within crystallites (XRD). It is found that the onset of amorphous precursor crystallization is observed at 575–600 ∘C/3 h and leads to the formation of Ln2(WO4)3 nanocrystalline powders with a monoclinic (sp. gr. C12/c1 (15)) structure. An increase in the calcination temperature leads to the growth of crystallite size and a decrease in microstrains. In the case of Dy2(WO4)3 an additional orthorhombic phase emerges (sp. gr. Pbcn(60)) at 1000 ∘C. It is shown that the local structure of all well-crystallized compounds being studied contains lanthanide ions in the form of Ln3+ and tungsten ions in the form of WO42− tetrahedra. The local structure in the monoclinic phase can be represented as a superposition of two non-equivalent tungstate tetrahedra: W(1)O4 (C2 site symmetry) and W(2)O4 (C1 site symmetry). The LnO8 polyhedra are strongly irregular, and the Ln3+ cations occupy low-symmetry sites.
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Control over crystal, local atomic and electronic structures of cerium chromates/chromites via the synthesis conditions
(2023) Popov, V. V.; Menushenkov, A. P.; Dubyago, F. E.; Yastrebtsev, A. A.; Ivanov, A. A.; Rudakov, S. G.; Попов, Виктор Владимирович; Менушенков, Алексей Павлович; Ястребцев, Алексей Алексеевич; Иванов, Андрей Анатольевич; Рудаков, Сергей Геннадьевич